Fire-resistant opaque window shade material and process of making same



Patented Jan. 10, 1950 FIRE-RESISTAN T MATERIAL AND SAME Charles C. Johnson Newburgh, N. Y.,

OPAQUE WINDOW SHADE PROCESS OF MAKING and Raymond E. Thomas, minors to E. I. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application May 28, 1947, serial No. 751,143

There are two distinct types of window shades;

namely, the opaque and translucent variety. For use in hotels, photographic dark rooms and similar rooms, there is a demand for shade cloth in light colors, which is absolutely opaque. In the past products of this type have been manufactured by coating each side of the fabric with suflicient coats of a pigmented coating composition to impart opaqueness; In the case of light colors, a great many coats were required on each side of the fabric to produce a completely opaque window shade cloth. This resulted in an overcoated product which was expensive to produce, liable to curl due to unbalanced coating, bulky and generally unsatisfactory. One solution to the problem is set forth by Quenelle in U. S. Patent 2,227,843, which issued January 7, 1941, wherein a base coating containing aluminum flakes is employed, which is then coated over with a light colored pigmented coating. Still further improvements are required, particularly with respect to resistance to cracking when creased sharply and fire-resistance.

Recent municipal ordinances, as well as certain state legislation and proposed federal legislation dealing with fire-resistant requirements for home and public building interior decorations, makes a fire-resistant window shade mandatory in many cases. It is important that many of the desirable properties existing in the present day cellulose derivative coated fabric window shade material be retained in the fire-resistant material, such as freedom from curl and distortion when hanging at a window, waterproofness, freedom from discoloration when exposed to sunlight and freedom from deterioration of both the coating and fabric.

The primary object of this invention is to provide a light colored, opaque window shade material "having all the desirable properties of the present day cellulose derivative coated fabric Claims. (Cl. 818) 2 window shade, and in addition fire-resistance.

According to the present invention, a light colored, fire-resistant, opaque window shade material is made by coating each side of a black dyed fabric with a polyvinyl chloride resin composition containing antimony oxide and titanium dioxide in certain critical proportions.

As indicated above, in order to obtain complete opacity for light colored coated fabric window shades, heretofore it has been necessary to apply sufficient coats of a pigmented composition to obtain an opaque film. Even when coating compositions pigmented to a greater extent than normalare'employed, it is necessary to apply so many coats to obtain opacity that the coated fabric is too thick and bulky to be wound and unwound on.a spring type roller commonly employed for windowshades. It was surprising and wholly unexpected when it was discovered that without changing the pigment content of the coating complete opacity can be obtained with considerable less coating if the fabric was dyed black before coating. It was also surprising that a fire-resistant coated fabric could be produced by coating a combustible fabric with a polyvinyl chloride composition containing as little as 20% antimony oxide, based on the combined weight of antimony oxide and polyvinyl chloride, and without a fire-resistant plasticizer.

The following specific examples are given to illustrate the prefered embodiment of the invention, although it is to be understood that the invention is in no way limited to these particular examples. In the formulae throughout the specification and claims, the parts are given on a weight basis. The proportions of the ingredients on a nonvolatile basis (i. e., in the absence of volatile solvents) are indicated by enclosing the per cent of each non-volatile material in parentheses.

EXAMPLE I A white window shade material completely one coat of the following base coating composition by means of a doctor knife.

Base coating composition Percent 30% solution of a copolvmer of approximately 90% vinyl chloride and 10% vinyl acetate in methyl ethyl ketone 76.4 Pigment-plasticizer mill base 23.6

1 liginent-piasticizer mill base:

Per cent Bone black pigment 28 Antimony oxide 28 Polypropylene glycol sebacate-.. Methyl ethyl ketone 16 The above composition was prepared in a conventional manner by first dissolving the copolymer resin in hot (160-1'70" F.) methyl ethyl kctone and separately preparing the pigmentplasticizer mill base by premixing the ingredients then grinding on a. three roll pigment grinding mill Top coating composition Per cent 13% solution of polyvinyl chloride in methyl ethyl ketone 69.5 Pigment-plasticizer mill base 1 30.5

I Pigment-plastiu'zer mill base:

Percent Titanium dioxide 44.9 Zinc oxide 14.9 Polypropylene glycol sebacate l3. 8 Methyl ethyl ketone 26.4

The following formulae represent the break down of the ingredients in the above base and top coating compositions:

Base Coating Top Coating Composition Composition Percent Percent Polyvinyl chloride. 9 (28.7) Copolymer of 90 parts vinyl chloride and 10 parts vinyl acetate.-- 22.9 5) Black pigment 6.6 15.5) Antimony oxide 6.6 (15. 5) Polypropylene glycol sebacate 6. 6 (l5. 5) 4. 2 (13.4) itaninm dioxide 13.7 (43.6) Zinc oxide 4.5 (14.3) Methyl ethyl ketone 57. 3 68. 6

Approximately 1.5 ounces per square yard of non-volatile components of the top coating composition was applied to each side of the fabric (total of 3 ounces per square yard). The fabric was passed through a heated chamber to expel the volatile solvent after each successive coat, same as indicated above. A suitable apparatus for drying the coated fabric is described by Anderson et al. in U. S. Patent 2,107,275, which issued February 8, 1938. A suitable apparatus for applying the coating is described by Edmondson in U. S. Patent 1,857,241, which issued May 10, 1932. The material had a total thickness of .007 inch, was light proof when examined directly over a 250 watt electric light bulb. The material was entirely satisfactory for use as a window shade mounted on conventional spring rollers. The material was also fire-resistant, as

determined by the method outlined hereinafter. 75 Methyl ethyl ketone There was no afterflame when the sample was removed from the flame, and the afterglow was 5-20 seconds.

The following method was employed for testing the fire-resistance of the coated fabric.

Three samples 1" x 10" are cut with their long dimension in the warp direction of the fabric, and three samples 1" x 16" are cut in the filler direction of the fabric. Each lot of three samples is cut from locations approximately equally spaced throughout the sample being tested, but at a distance from the selvage amounting to at least 10% of the width. The samples are suspended vertically from a clamp covering the upper inch of the length with the lower end 4 inches from the top of a Tlrrill burner. The flame from the burner is adjusted to a height of 5 inches with a blue cone of 1 /2 inches in height. The lower 1% inches of the sample is suspended in the flame. The flame is applied to the center of the lower end of the vertically suspended sample for ten seconds, then the sample is withdrawn. The duration of the flaming and afterglowing of the sample is noted. If the sample is consumed completely in the ten seconds, the material is rated as highly flammable. Material which has an after-flame of less than two seconds and an afterglow of less than 20 seconds is considered commercially fire-resistant. In the base coating composition, the ratio of total pigment to fllm former is 1 to 1.7. The ratio of antimony oxide to black pigment depends on the particular black pigment. Carbon blacks and similar finely divided black pigments usually require less pigment to obtain equal degree of opacity. It is important that the amount of antimony oxide in the coating next to the fabric not drop below 20% of the combined weight of antimony oxide and the polyvinyl chloride resin, since this is the combination that imparts fire-resistance to the coated fabric.

EXAMPLE II A fire-resistant ecru colored opaque window shade was produced by coating each side with approximately 2 ounces per square yard of nonvolatile coating (total of approximately 4 ounces per square yard) with the following composition:

Methyl ethyl ketone 26.4

The following is a breakdown of the ingredients of the above coating composition:

Per cent Polyvinyl chloride 9.0 (28.7) Antimony oxide 3.0( 9.6) Zinc oxide 1.2( 3. Chrome orange .l( .3) Chrome yellow .l .3) Bone black .l .3) Titanium dioxide 13.70136) Polypropylene glycol sebacate 4.2 (13.4) 68.6

The above coating composition was prepared and applied in the same manner as outlined above in Example I. In this case the base coating composition of the more soluble polymer employed in Example I was omitted entirely. The coated fabric was entirely satisfactory for use as a. window shade material and was opaque when examined over a 250 watt light.

In the final surface coating compositions, it will be noted that the ratio of the total pigment content (zinc oxide plus titanium dioxide) to polyvinyl chloride film former is 57.9 parts of the former to 28.7 parts of the latter; i. e., a ratio of 2: 1. For the purposes of this invention the ratio of the total pigment to film former in the surface coating may vary between 60 parts of total pigment to 40 parts film former and 70 parts of total pigment to 30 parts of film former. This degree of pigmentation of polyvinyl chloride coatings is much greater than that employed in conventional coatings. It was surprising that the dried film had sufiicient film strength to resist cracking when sharply creased under pressure, since the coating contains two parts of pigment to one part of film former.

The high ratio of titanium dioxide pigment to film former in the present invention permits the covering of the black dyed fabric with a minimum amount of light colored coatings. The titanium dioxide contributes to the high degree of opacity of the thin coatings, and the zinc oxide acts as an acid acceptor or neutralizer for any acid decomposition products that might be formed over long periods of continuous exposure. The zinc oxide is preferred for use in the above compositions, but it is to be understood that it is not essential as is the case of titanium dioxide in order to obtain a maximum of opacity with a minimum of light colored coatings. As shown in Example II, the surface coating may be tinted with colored pigments to give light colored shades. The amount of colored pigments required for tinting is relativelysmall, and is not sufficient to substantially contribute to the opacity of the relatively thin coatings.

A suitable grade of polypropylene glycol sebacate for use in this invention is sold on the open market by Resinous Products and Chemical Company under the trade designation, Paraplex G25. This particular plasticizer is preferred since it is the least volatile of all the commercially available vinyl resin plasticizers. Vinyl resin films plasticized with polypropylene glycol sebacate have very little tendency to stiffen when exposed to sunlight.

The preferred embodiment of the invention may be varied to the extent that fire-resistant plasticizers may be employed with the vinyl resin coatings; such as, e. g., tricresyl phosphate, trioctyl phosphate and triphenyl phosphate or mixtures thereof with some sacrifice of aging properties. Blends of the polypropylene glycol sebacate with tricresyl phosphate, triphenyl phosphate and/or trioctyl phosphate may also be used.

In the case of the base coating composition in Example I, the invention is not to be limited to the particular vinyl halide copolymer disclosed. The copolymer of 90 parts vinyl chloride and parts of vinyl acetate is preferred for the base coating due to its solubility in methyl ethyl ketone, which permits a greater deposition of non-volatile components per coat due to increased non-volatile portion of the composition. The 90/10 copolymer mentioned above is, howmodified polyvinyl chloride.

ever, too soft and lacking in resistance to cracking when creased sharply to be used in the top coating composition. The top coating composition requires the use of the less soluble polymers in order to obtain sufficient film strength with the highloading of the composition with pigments. Copolymers of 95 parts vinyl chloride and 5 parts vinyl acetate, and 95 parts vinyl chloride and 5 parts diethyl fumarate may be employed in the surface coating since these copolymers give films havingtensile strength comparable to un- In the appended claims the copolymer resins and unmodified polyvinyl chloride resins mentioned throughout the specification are referred to as polyvinyl chloride resins."

For smooth operation of spring type roller window shades, the shade material should not be over .013" thick and preferably less than .010". If the shade material is over .013" thick, it is very bulky when the shade is completely rolled up on the spring roller.

The principal advantage of the invention is the production of an absolutely opaque light colored, fire-resistant, cloth coated window shade without bulkiness. A further advantage is dryness of the coating coupled with resistance to deterioration of both the coating and fabric when exposed over a period of several years to sunlight.

It is apparent that many widely different embodiments of this invention may be made without departing from the spirit and scope thereof, and therefore, it is not intended to be limited except as indicated in the appended claims.

We claim:

1. A fire-resistant, light colored, opaque window shade material comprising a black .fabric coated approximately equally on each side with a coating composition comprising a polyvinyl chloride resin, antimony oxide, titanium dioxide and plasticizer, the ratio of the total pigment content to the resin being between parts of total pigment to 40 parts of resin and parts of total pigment to 30 parts of resin, at least 50% of the total pigment content in the coating being titanium dioxide and the antimony oxide being present in amount of at least 20% of the combined weight of antimony oxide and polyvinyl chloride resin, the total weight of the coatings being less than about 4 ounces per square yard.

2. The product of claim 1 in which the coated material is less than .013 inch in thickness.

3. The product of claim 1 in which the vinyl chloride resin is a homo-polyvinyl chloride.

4. The product of claim 1 in which the vinyl resin is a copolymer of about 95 parts of vinyl chloride and 5 parts of vinyl acetate.

5. The product of claim 1 in which the vinyl resin is a copolymer of about 95 parts of vinyl chloride and 5 parts of diethyl fumarate.

6. A fire-resistant, light colored, opaque window shade material comprising a black fabric base coated approximately equally on each side with a base coating composition comprising a polyvinyl chloride resin, antimony oxide and plasticizer, the antimony oxide being present in amount not less than 20% of the combined weight of antimony oxide and polyvinyl chloride resin, a second coating applied approximately equally to both sides over the first mentioned coating comprising polyvinyl chloride resin, titanium dioxide and plasticizer, the ratio of the total pigment content to resin being between 60 parts of total pigment to 40 parts of resin and 70 parts of total pigment to 30 parts of resin, the titanium dioxide Per cent Polyvinyl chloride resin; 28.7 Antimony oxide 9.6 Titanium dioxide 43.6 Other pigments 4.7

Polypropylene glycol sebacate 13.4

8. The process of preparing fire-resistant, light colored, opaque window shade material which comprises dyeing a woven cotton sheeting black, coating said dyed sheeting approximately equally on each side with a composition comprising a polyvinyl chloride resin, antimony oxide and titanium dioxide pigments, and plasticizer, dispersed in a volatile liquid, the ratio of total pigment content to the polyvinyl chloride resin being between 60 parts of total pigment to 40 parts of polyvinyl chloride resin and 70 parts or total pigment to 30 parts of polyvinyl chloride resin, at least 50% of the total pigment content in said coating being titanium dioxide, the antimony oxide being present in amount not less than of the combined weight of antimony oxide and polyvinyl chloride resin, and drying the coating after each successive coat by passing through a heated chamber, the total weight or the coatings being less than about 4 ounces per square yard.

9. The process of claim 8 in which the cotton sheeting is coated with about 2 ounces per square yard on each side of the following composition:

Polypropylene glycol sebacate 13.4

10. The process of preparing fire-resistant, light colored, opaque window shade material, which comprises dyeing woven cotton sheeting black, coating said dyed sheeting approximately equally on each side with a composition comprising polyvinyl chloride resin, antimony oxide and plasticizer dispersed in a volatile liquid, the antimony oxide being present in amount not less than 20% of the combined weight of antimony oxide and polyvinyl chloride resin, applying approximately equal amounts on each side over said first mentioned coating a second coating comprising polyvlnyl chloride resin, titanium dioxide and plasticizer dispersed in a volatile liquid, the ratio of total pigment to the polyvinyl chloride resin being between 60 parts of total pigment to parts oi polyvinyl chloride resin and 70 parts 01' total-pigment to 30 parts of polyvinyl chloride resin, at least of the total pigment in said second coating being titanium dioxide, and drying the coating after each successive coat by passing through a heated chamber, the total weight of the coatings being less than about 4 ounces per square yard.

CHARLES C. JOHNSON. RAYMOND E. THOMAS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 35 Number Name Date 1,586,189 Fletcher May 25, 1926 2,299,612 Clayton et al. Oct. 20, 1942 2,395,922 Timmons Mar. 5, 1946 2,413,163 Bacon Dec. 24, 1946 

10. THE PROCESS OF PREPARING FIRE-RESISTANT, LIGHT COLORED, OPAQUE WINDOW SHADE MATERIAL, WHICH COMPRISES DYEING WOVEN COTTON SHEETING BLACK, COATING SAID DYED SHEETING APPROXIMATELY EQUALLY ON EACH SIDE WITH A COMPOSITION COMPRISING POLYVINYL CHLORIDE RESIN, ANTIMONY OXIDE AND PLASTICIZER DISPERSED IN A VOLATILE LIQUID, THE ANTIMONY OXIDE BEING PRESENT IN AMOUNT NOT LESS THAN 20% OF THE COMBINED WEIGHT OF ANTIMONY OXIDE AND POLYVINYL CHLORIDE RESIN, APPLYING APPROXIMATELY EQUAL AMOUNTS ON EACH SIDE OVER SAID FIRST MENTIONED COATING A SECOND COATING COMPRISING POLYVINYL CHLORIDE RESIN, TITANIUM DIOXIDE AND PLASTICIZER DISPERSED IN A VOLATILE LIQUID, THE RATIO OF TOTAL PIGMENT TO THE POLYVINYL CHLORIDE RESIN BEING BETWEEN 60 PARTS OF TOTAL PIGMENT TO 40 PARTS OF POLYVINYL CHLORIDE RESIN AND 70 PARTS OF TOTAL PIGMENT TO 30 PARTS OF POLYVINYL CHLORIDE RESIN, AT LEAST 50% OF THE TOTAL PIGMENT IN SAID SECOND COATING BEING TITANIUM DIOXIDE, AND DRYING THE COATING AFTER EACH SUCCESSIVE COAT BY PASSING THROUGH A HEATED CHAMBER, THE TOTAL WEIGHT OF THE COATINGS BEING LESS THAN ABOUT 4 OUNCES PER SQUARE YARD. 